Top Weather Stories of 2009 for Northern IL and Northwest IN

Top Weather Stories of 2009 for Northern Illinois and Northwest Indiana

by Jim Allsopp, Warning Coordination Meteorologist

January 9-10 Heavy Snow over the Northern Chicago Metro Area

Six inches to a foot of snow fell over parts of north central and northeast Illinois from Winnebago County to Lake County, southward to parts of Kane, Du Page, and Cook Counties. The heaviest snowfall included 12 inches at Evanston, 11.1 inches at Beach Park, and 10.2 inches at O’Hare Airport.

Northern Illinois and northwest Indiana experienced brutally cold weather. Low temperatures were around 15 to 30 below zero and winds chills dropped to 30 to 50 below zero. The coldest temperatures occurred the morning of the 16th, including -32 at Dixon, and -31 at Aurora. Officially at Chicago O’Hare, the low was -18. This was the coldest temperature recorded since 1996. Rockford set an all time record for the date with -25. This was the third coldest temperature ever recorded at Rockford. Wind chills peaked at -53 in Rochelle, -51 at Aurora, -35 at Rockford and -34 at O’Hare.

January 2009 ended up being the 10th coldest January on record for Chicago, with an average temperature of 15.9 degrees. That was more than 6 degrees below normal. Rockford had its 16th coldest January with an average temperature of 13.8.

Three tornadoes were documented over Livingston and Kankakee Counties. The first twister struck rural Livingston County about 5 miles southwest of Pontiac. It caused EF0 damage to a garage and a barn. Another tornado developed in Kankakee County about 5 miles northwest of Momence. This tornado caused EF1 damage to farm buildings and trees. A third tornado damaged farm buildings just west of Grant Park. It was rated EF1. Other storms over northern Illinois and northwest Indiana produced heavy rain and localized flooding, damaging wind gusts, and hail to the size of nickels. The storms occurred along a strong cold front. Behind the front winds gusted to 50 to 60 mph.

Chicago had 3.39 inches of rain in February, 5.20 inches in March, and 5.19 inches in April. February was the twelfth wettest on record, March was the fifth wettest, and April was the eighteenth wettest. The three month rainfall total of 13.78 inches was the wettest February through April ever, surpassing the 13.31 inches that fell in 1983.

Rockford had 5.80 inches of rain in March, making it the second wettest March of all time. February and April were also wetter than normal, but did not rank in the top twenty all time wet months.

As a result of the wet weather, many streams were in flood for extended periods of time well into spring. The wet weather also delayed many farmers from getting into fields to plant crops.

June 19 Severe Storms, Tornado, and Flash Flooding

Thunderstorms brought heavy downpours and hail to northern Illinois and the northern Chicago metro area during the morning. O’Hare Airport had 3.48 inches of rain. Streets, underpasses, and basements were flooded. Hail from penny size to golf ball size pelted the area. Later in the evening more thunderstorms produced winds gusts of 50 to 70 mph across northern Illinois, damaging trees, and farm buildings. An EF1 tornado struck just southeast of Woodstock, where a garage was destroyed, two commercial buildings were heavily damaged, and many trees were damaged or uprooted.

Map of tornado path near Woodstock June 19, 2009 from NOAA/NWS

Garage destroyed near Woodstock – photo from NOAA/NWS

Trees uprooted near Woodstcok – photo from NOAA/NWS

In addition, heavy rain caused flash flooding in Ogle County where campers were evacuated and some roads were closed or damaged by flood waters. Flash flooding also occurred in Rockford. The flooding may have contributed to a train derailment and explosion on the southeast side of the city.

Overall it was a cool summer over northern Illinois and northwest Indiana. Chicago only had four days in with temperatures in the 90s for the whole summer. Three of them came back to back to back from June 23rd through June 25th. The temperature hit 94 on all three days. There were several more days in the mid to upper 80s in late June. Rockford had four straight days in the lower 90s from the 22nd to the 25th of June. There were five heat related deaths in the Chicago metro area as a result of the intense heat.

August 19 Tornado Outbreak

Severe thunderstorms developed in the afternoon and several tornadoes were reported. An EF1 tornado struck near Pittwood in Iroquois County. The twister flattened corn, damaged garages, sheds and other farm structures, as well as knocking down large trees and limbs. Two more tornadoes occurred near Elburn and Lilly Lake in northern Kane County. One was rated EF1 with most of the damage to trees and crops. The other was EF0 with damage to trees in a subdivision.

The most destructive tornado of the day struck Chesterton, Indiana. The tornado was rated EF2. It damaged the roof of a school, unroofed a warehouse and an apartment building. Altogether, more than 200 buildings and homes were damaged. Numerous trees and limbs were also blown down.

Chicago had its fifth coolest summer since 1942. There were only four days in the 90s but a record 30 days with a temperature that failed to climb above 75. Rockford had its third coolest summer on record. Rockford also only had four days in the 90s but 25 days of 75 or under.

Cool, Cloudy, Wet October

Chicago had the second lowest amount of sunshine ever recorded for the month of October. Only 33% of the possible sunshine was received. It was the eleventh coolest October on record with an average temperature of 48.9, which was 3.2 degrees below normal. It was the ninth wettest with 6.04 inches of rain, which was 3.33 inches above normal. There was measurable rain on 19 days, which tied a record for the most rainy days in the month of October.

Rockford had its seventh coolest October with an average temperature of 47.2, which was 3.8 degrees below normal. It was Rockford’s fifth wettest October with 5.94 inches, which was 3.42 inches above normal.

In contrast, November was the 8th warmest on record in Chicago, with an average temperature of 45.4 degrees, which was 6.1 degrees above normal. Rainfall was below normal and sunshine was above normal. Rockford had the 6th warmest November on record with an average of 43.7 degrees, which was 6.5 degrees above normal. Rainfall was also below normal.

December 8-10 Early Winter Storm

An intense low pressure system moved from Missouri to near Chicago to Lower Michigan on December 8 and 9. The atmospheric pressure dropped to 28.91 inches of mercury at O’Hare Airport the morning of the 9th. The storm produced 6 to 9 inches of snow across north central Illinois and the far northwest suburbs of Chicago, including 9.5 inches at Dixon, 8.2 inches at Rockford and 7.8 inches at Bull Valley. Much of the Chicago metro area received a mix of snow, sleet, and rain. In the wake of the low, winds gusted to 40 to 50 mph. By the morning of the 10th, temperatures plummeted to zero to 5 below zero with wind chills of 20 to 25 below zero.